Technical Field
The present disclosure generally relates to powerline communications. More particularly, but not exclusively, the present disclosure relates to powerline communications as applied to vehicles powered by conductive or inductive rails.
Description of the Related Art
In many industrial, manufacturing, commercial, and other settings, powerline communication mediums are employed to distribute power to one or more nodes in a system. Some or all of the nodes in the system use the conduits that pass power to concurrently communicate data.
In certain known vehicle systems, for example, carts travel on rails in a factory or warehouse environment. In the system, the carts use the rails for guidance, as a conduit to transfer electrical power to the carts, and as a communication medium to transfer data between carts and other communication-capable nodes in the system. These systems are conventionally used for automated distribution of components in warehouses or the factory floor.
Within these conventional systems, the rail is provided with its own power supply. The power supply sources power to each cart operating on the rail system. Also within the system, the rail has an associated PLC central coordinator, which may also be referred to as a central controller (CCo). The CCo performs several network management functions such as association, authentication, node admission control, quality of service (QoS) guarantees, and the like. As carts travel within the system, the carts are in communication with the CCo passing and receiving data associated with position, speed, operational characteristics, functional characteristics, and the like.
In an exemplary conventional system, the rail lines are formed with long rails or rail segments joined as a single electrical and communicative conduit. A single powerline communications (PLC) central coordinator (CCo) directs communications in the logical PLC network. Carts move constantly throughout the system as on a single continuous rail, and generally, the carts move between destinations at a constant speed.
In the exemplary conventional system, each cart operates as a single PLC communications node within the logical PLC network. Communications with each PLC node (i.e., cart) may occur, for example, according to a time division multiple access (TDMA) protocol. The PLC CCo may operate as a master that polls each node (i.e., cart), and in response, the node is granted a particular session window within which data is communicated. The duration of each session window can be selected based on the speed of carts within the system, which may be substantially constant. In the exemplary conventional system, for example, a session window is 128 milliseconds (ms) per node. Accordingly, it may be recognized that a conventional powerline communications network may have an upper limit of operating PLC nodes (i.e., carts) based on the fixed session window time set by the PLC CCo for communicating with each cart.
Also in the conventional system, the PLC CCo is communicatively coupled to a second computing system that is separate from the PLC network. The second computing system, which may be accessible via a different network (e.g., Ethernet), accepts information associated with the PLC network and information associated with the carts operating on the rail system. The second computing system also provides information and directions to the PLC CCo and the carts.
All of the subject matter discussed in the Background section is not necessarily prior art and should not be assumed to be prior art merely as a result of its discussion in the Background section. Along these lines, any recognition of problems in the prior art discussed in the Background section or associated with such subject matter should not be treated as prior art unless expressly stated to be prior art. Instead, the discussion of any subject matter in the Background section should be treated as part of the inventor's approach to the particular problem, which in and of itself may also be inventive.